Histograms of the (normalized) capacitive couplings of the barrier gates to the transition lines (red for vUB and blue for vLB virtual gates) obtained by analysing three different sets of transition line coupled to virtual plunger vP3. The middle and bottom panels are extracted from the shift in the transition lines at ~(–20, –63) and (–15, –7) in a , respectively. The top panel (relative to dot Q3t) is obtained from a measurement shown in Supplementary Fig. 14g,h , where the transition line is more visible. The red and blue backgrounds are added to emphasize the two barriers with the highest couplings. The data points correspond to the peak of the chart bars as well as the centres of the error bars. Each error bar is the standard deviation of the parameter obtained from the linear fit.
